Helleborus × sternii Blackthorn Group
hellebore Blackthorn Group
Blackthorn Group are evergreen perennials to 45cm with purplish biennial stems bearing leaves composed of three bluish-green, pale-veined leaflets. Nodding, pale pinkish-green flowers 3-5cm in width are borne in open clusters
Size
Ultimate height
0.1–0.5 metresTime to ultimate height
2–5 yearsUltimate spread
0.1–0.5 metresGrowing conditions
Moisture
Moist but well–drainedpH
Alkaline, NeutralColour & scent
| Stem | Flower | Foliage | Fruit | |
| Spring | Green Purple | Green Pink | Blue Green | |
|---|---|---|---|---|
| Summer | Green Purple | Blue Green | ||
| Autumn | Green Purple | Blue Green | ||
| Winter | Green Purple | Green Pink | Blue Green |
Position
- Full sun
- Partial shade
Aspect
East–facing or South–facing or North–facing or West–facing
Exposure
Sheltered Hardiness
H4Botanical details
- Family
- Ranunculaceae
- Native to the UK
- No
- Foliage
- Evergreen
- Habit
- Clump forming
- Potentially harmful
- Harmful if eaten, skin irritant. Wear gloves and other protective equipment when handling
- Genus
Helleborus can be rhizomatous, herbaceous or semi-evergreen perennials forming a clump of pedate basal leaves, or evergreen with erect, leafy stems. Large, bowl-shaped flowers are borne in loose clusters in late winter or spring
- Name status
Accepted
How to grow
Cultivation
Thrives in neutral to alkaline soils that are moist, fertile and humus-rich. Partial shade is ideal but can tolerate full sun. Provide shelter from strong, cold winds. Mulch annually in autumn
Propagation
Propagate by seed in pots in a cold frame as soon as seed is ripe or propagate by division after flowering in early spring or late summer. Named cultivars do not come true from seed
Suggested planting locations and garden types
- Cottage and informal garden
- Wildlife gardens
- Cut flowers
- Flower borders and beds
- Underplanting of roses and shrubs
Pruning
Remove faded or damaged foliage as the flowers appear
Pests
May be susceptible to hellebore aphid, hellebore leaf miner and snails
Diseases
May be susceptible to hellebore leaf spot and hellebore black death
Get involved
The Royal Horticultural Society is the UK’s leading gardening charity. We aim to enrich everyone’s life through plants, and make the UK a greener and more beautiful place.